CN112368926A - Power conversion device - Google Patents
Power conversion device Download PDFInfo
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- CN112368926A CN112368926A CN201980045560.XA CN201980045560A CN112368926A CN 112368926 A CN112368926 A CN 112368926A CN 201980045560 A CN201980045560 A CN 201980045560A CN 112368926 A CN112368926 A CN 112368926A
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- 238000006243 chemical reaction Methods 0.000 title claims abstract description 47
- 239000003990 capacitor Substances 0.000 claims abstract description 55
- 238000003780 insertion Methods 0.000 claims abstract description 4
- 230000037431 insertion Effects 0.000 claims abstract description 4
- 238000001914 filtration Methods 0.000 claims description 3
- 238000002360 preparation method Methods 0.000 claims description 2
- 238000010586 diagram Methods 0.000 description 13
- 230000001360 synchronised effect Effects 0.000 description 10
- 238000004088 simulation Methods 0.000 description 8
- 230000000694 effects Effects 0.000 description 7
- 230000004048 modification Effects 0.000 description 5
- 238000012986 modification Methods 0.000 description 5
- 230000007257 malfunction Effects 0.000 description 3
- 230000003071 parasitic effect Effects 0.000 description 2
- 230000001629 suppression Effects 0.000 description 2
- 230000006866 deterioration Effects 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
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Classifications
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/12—Arrangements for reducing harmonics from ac input or output
- H02M1/126—Arrangements for reducing harmonics from ac input or output using passive filters
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/14—Arrangements for reducing ripples from dc input or output
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/01—Resonant DC/DC converters
- H02M3/015—Resonant DC/DC converters with means for adaptation of resonance frequency, e.g. by modification of capacitance or inductance of resonance circuit
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
- H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
- H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
- H02M3/158—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators including plural semiconductor devices as final control devices for a single load
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
- H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
- H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
- H02M3/158—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators including plural semiconductor devices as final control devices for a single load
- H02M3/1584—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators including plural semiconductor devices as final control devices for a single load with a plurality of power processing stages connected in parallel
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
- Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes
Abstract
The power conversion device includes: at least one switching circuit that generates an alternating-current voltage by switching a direct-current voltage at a prescribed switching frequency; and a filter circuit that low-pass filters the alternating voltage from the switch circuit. The filter circuit has: a first bypass capacitor that bypasses noise of a first frequency component in the alternating-current voltage from the switching circuit; a second bypass capacitor that bypasses noise of a second frequency component lower than the first frequency component in the alternating-current voltage from the switching circuit; and at least one inductor interposed between the first bypass capacitor and the second bypass capacitor. The inductance of the inductor is set so that the resonance frequency of the filter circuit becomes smaller than the switching frequency due to the insertion of the inductor.
Description
Technical Field
The present invention relates to a power conversion device such as a DC/DC conversion device.
Background
In a power converter that performs power conversion by on/off control of a switching element, switching control is generally performed at a switching frequency of 20kHz or higher, and therefore high-frequency switching noise due to on/off of the switching element is generated. This causes a problem that malfunction such as malfunction or functional stoppage of the electronic device occurs.
For example, fig. 9 shows a configuration of a power conversion device 101 of conventional example 1 disclosed in patent document 1. In fig. 9, the power converter 101 includes a power filter circuit 110 and a voltage converter circuit 120. Here, the power supply filter circuit 110 is configured by connecting in parallel a first filter circuit 111 including a capacitor 111a and a second filter circuit 112 including a series circuit of a capacitor 112a and a resistor 112 b. The voltage conversion circuit 120 includes a switching circuit 121 including switching elements 121a and 121b, and a low-pass filter 122 including a coil 122a and a capacitor 122 b.
In the conventional power converter, it is known that a high-frequency ringing noise (100MHz to several hundreds MHz) is generated in a frequency band at the time of output due to the influence of parasitic inductance. In the power converter of conventional example 1 of fig. 9, in order to reduce high-frequency noise, a first filter circuit 111 including a large-capacity capacitor 111a having a large capacity and a second filter circuit 112 including a small-capacity capacitor 112a for noise countermeasure are added to stabilize a drive pulse signal and reduce high-frequency noise.
Further, in the power converter of conventional example 2 disclosed in patent document 2, a bypass capacitor for high frequency and a bypass capacitor for low frequency provided in the subsequent stage of the switching circuit are connected by a small inductance, and thereby the power converter operates in a high frequency region where switching noise is small.
Documents of the prior art
Patent document
Patent document 1: japanese patent laid-open publication No. 2014-103842
Patent document 2: japanese patent No. 6207751
Disclosure of Invention
Problems to be solved by the invention
However, in conventional example 2, parasitic inductance (hereinafter, referred to as wiring inductance) due to the wiring is inevitably present between the high-frequency bypass capacitor and the low-frequency bypass capacitor. Therefore, a resonance phenomenon occurs due to these LC circuits.
Fig. 10 is a graph showing a relationship between the resonance frequency fr and the wiring inductance for explaining the problem of the present invention. As shown in fig. 10, as the resonance frequency fr is shifted from the switching frequency fSWThe frmax is changed to the upper limit thereof and the wiring inductance is lowered. However, at the resonant frequency fr and the switching frequency fSWIn the case of coincidence, there is a problem that the switching noise is further amplified by the resonance phenomenon.
In addition, it is expected that the noise level in the high frequency region will further increase with the progress of higher frequency of the next-generation power device in the future.
The present invention has been made to solve the above problems, and an object of the present invention is to provide a power conversion device capable of reliably reducing switching noise in the power conversion device as compared with the conventional art.
Means for solving the problems
A power conversion device according to an aspect of the present invention includes:
at least one switching circuit for switching at a predetermined switching frequency (f)SW) Switching the DC voltage to generate an AC voltage; and
a filter circuit for converting the AC voltage from the switch circuit into a DC voltage by low-pass filtering and outputting the DC voltage to a load,
it is characterized in that the preparation method is characterized in that,
the filter circuit has:
a first bypass capacitor that bypasses noise of a first frequency component in the alternating-current voltage from the switching circuit;
a second bypass capacitor that bypasses noise of a second frequency component lower than the first frequency component in the alternating-current voltage from the switching circuit; and
at least one inductor interposed between the first bypass capacitor and the second bypass capacitor,
the inductance (L) of the inductor is set so that the resonance frequency (fr) based on the filter circuit becomes higher than the switching frequency (f) due to the insertion of the inductorSW) Is small.
ADVANTAGEOUS EFFECTS OF INVENTION
Therefore, according to the power conversion device of the present invention, it is possible to avoid complication of the circuit configuration, to reliably reduce switching noise in the power conversion device as compared with the conventional art, and to efficiently operate.
Drawings
Fig. 1A is a circuit diagram showing a configuration example of a power converter according to embodiment 1.
Fig. 1B is a circuit diagram showing a configuration example of a power conversion device according to a modification of embodiment 1.
Fig. 2 is a circuit diagram showing a configuration example of a non-synchronous power conversion device having a boosting function according to embodiment 2.
Fig. 3 is a circuit diagram showing a configuration example of a synchronous power conversion device having a boosting function according to embodiment 3.
Fig. 4 is a circuit diagram showing a configuration example of a synchronous power conversion device having a boosting function according to embodiment 4.
Fig. 5 is a circuit diagram showing a configuration example of a synchronous power conversion device having a step-up function according to embodiment 5.
Fig. 6 is a graph showing the simulation result of the power conversion apparatus of fig. 3, and is a frequency characteristic of the fluctuation Ie of the efficiency Ef and the execution current.
Fig. 7 shows simulation results of the power conversion device shown in fig. 3, showing the resonant frequency fr and the switching frequency fSWTiming charts of the waveforms of the respective operation signals when they do not match (70 kHz).
Fig. 8 shows simulation results of the power conversion device shown in fig. 3, showing the resonant frequency fr and the switching frequency fSWTiming charts of the waveforms of the respective operation signals when they are matched at (70 kHz).
Fig. 9 is a circuit diagram showing a configuration of a power converter of conventional example 1.
Fig. 10 is a graph showing a relationship between the resonance frequency fr and the wiring inductance for explaining the problem of the present invention.
Fig. 11 is a graph showing the frequency characteristics of switching noise, which is a problem of the power converter of conventional example 2.
Fig. 12 is a graph showing the frequency characteristics of switching noise showing the operational effects obtained by the means for solving the problem in the present embodiment.
Detailed Description
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the same components are denoted by the same reference numerals.
Fig. 1A is a circuit diagram showing a configuration example of a power conversion device of embodiment 1. In fig. 1A, the power conversion device of embodiment 1 is interposed between a dc voltage source 11 and a load 15. The power converter includes a switching circuit 10 and a filter circuit 30. The switching circuit 10 is controlled to have a predetermined switching frequency (f)SW) The dc voltage from the dc voltage source 11 is switched to generate an ac voltage, and the ac voltage is output to the filter circuit 30. Followed byThe filter circuit 30 converts the ac voltage from the switching circuit into a dc voltage by low-pass filtering, and outputs the dc voltage to the load 15.
The switching circuit 10 includes: a switching element that switches a direct-current voltage; and a control circuit 20 that generates a drive signal for driving the switching element by on/off control at a prescribed duty ratio.
The filter circuit 30 is configured to include bypass capacitors 12 and 13 and inductors 14A and 14B. The ac voltage from the switching circuit 10 is applied to both ends of the bypass capacitor 12, one end of the bypass capacitor 12 is connected to one end of the bypass capacitor 13 via the inductor 14A, and the other end of the bypass capacitor 12 is connected to the other end of the bypass capacitor 13 via the inductor 14B. Here, the bypass capacitor 12 bypasses the switching noise of the first frequency component (relatively high frequency component) in the alternating voltage from the switching circuit 10. The bypass capacitor 13 bypasses noise of a second frequency component (relatively low frequency component) lower than the first frequency component in the alternating voltage from the switching circuit 10. The total inductance (L) of the inductors 14A, 14B is set so that the resonant frequency fr of the filter circuit 30 becomes higher than the switching frequency f due to the insertion of the inductors 14A, 14BSWIs small.
That is, in the present embodiment, the capacitance of the bypass capacitor 12 is C1The capacitance of the bypass capacitor 13 is set to C2Time, switching frequency fSWAnd the resonance frequency (fr) are set as follows.
[ equation 1]
In the present embodiment, one of the two inductors 14A and 14B may be deleted. The inductors 14A and 14B may be at least one of a wiring inductor, an assembled inductor, and an assembled coil.
In the power converter configured as described above, the bypass capacitors 12 and 13 are connected between the power supply line and the ground line between the switching circuit 10 and the load 15 for the purpose of avoiding variation in the dc voltage of the dc voltage source 11 during operation of the power converter. Here, the bypass capacitor 12 has a function of returning a high-frequency switching noise component generated from the switching circuit 10, and the bypass capacitor 13 has a function of returning a low-frequency switching noise component. The inductors 14A, 14B have the effect of lowering the resonance frequency between the bypass capacitors 12, 13. In order to satisfy the capacitances of the bypass capacitors 12 and 13, a plurality of capacitors may be connected in parallel or in series.
As described above, according to the power converter of the present embodiment, it is possible to avoid complication of the circuit configuration, to surely reduce switching noise in the power converter as compared with the conventional art, and to efficiently operate. Here, a component with relatively small ripple can be selected as the capacitor to be inserted, and an inductor is inserted to suppress an overcurrent, so that the heat radiator for the switching element can be made smaller than in the related art.
Further, the modification of embodiment 1 can be applied to embodiments 2 to 5.
A modification of embodiment 1.
Fig. 1B is a circuit diagram showing a configuration example of a power conversion device according to a modification of embodiment 1. The power conversion apparatus of fig. 1B differs from the power conversion apparatus of fig. 1A in the following points.
(1) Instead of 1 switching circuit 10, M switching circuits having a plurality of switching circuits 10-1 to 10-M are provided. Each of the switch circuits 10-1 to 10-M may have a control circuit 20-1 to 20-M for generating a drive signal for driving the switch element, or one control circuit may drive each of the switch elements of the plurality of switch circuits 10-1 to 10-M.
The power conversion device according to the modification of embodiment 1 configured as described above has the same operational advantages as the power conversion device according to embodiment 1.
Fig. 2 is a circuit diagram showing a configuration example of a non-synchronous power conversion device having a boosting function according to embodiment 2. The power converter of embodiment 2 is a power converter of fig. 1, and the circuit configuration of the switching circuit 10 is shown in detail, and only the differences will be described below.
In fig. 2, the switching circuit 10 includes a boosting reactor 16, a switching element Q1 formed of, for example, a MOSFET, an IGBT, or the like, a diode D1, and a control circuit 20. A dc voltage from the dc voltage source 11 is applied to both the drain and source of the switching element Q1 via the reactor 16, and the drain of the switching element Q1 is connected to one end of the bypass capacitor 12 via the diode D1. The control circuit 20 generates a drive signal S1 for driving the switching element Q1 by on/off control at a prescribed duty ratio, and applies to the gate of the switching element Q1.
The power converter of embodiment 2 configured as described above has the same operational advantages as the power converter of embodiment 1 except that it has the asynchronous step-up function.
Embodiment 3.
Fig. 3 is a circuit diagram showing a configuration example of a synchronous power conversion device having a boosting function according to embodiment 3. The power converter of embodiment 3 has the following differences from the power converter of fig. 2.
(1) Instead of the switch circuit 10, a switch circuit 10A is provided.
(2) The switching circuit 10A includes a boost reactor 16, switching elements Q1 and Q2 formed of, for example, MOSFETs or IGBTs, and a control circuit 20A.
In fig. 3, a dc voltage from a dc voltage source 11 is applied to both ends of the drain and source of a switching element Q1 via a reactor 16, and the drain of a switching element Q1 is connected to one end of a bypass capacitor 12 via the source and drain of a switching element Q2. The control circuit 20A generates drive signals S1, S2 for driving the switching elements Q1, Q2 by on/off control at a predetermined duty ratio and in synchronization with each other for different periods, and applies the drive signals S1, S2 to the gate of the switching element Q1.
The power conversion device according to embodiment 3 configured as described above has the same operational advantages as the power conversion device according to embodiment 2, except that it has a synchronous step-up function.
Embodiment 4.
Fig. 4 is a circuit diagram showing a configuration example of a synchronous power conversion device having a boosting function according to embodiment 4. The power converter of embodiment 4 has the following differences from the power converter of fig. 3.
(1) A first inductor L1 having a Common Mode Choke (CMC)17 in place of the inductor 14A.
(2) A second inductor L2 having a Common Mode Choke (CMC)17 in place of the inductor 14B.
Here, the common mode choke coil (CMC)17 is provided particularly for removing common mode noise. Instead of the common mode choke coil (CMC)17, two inductors L1 and L2 may be used. In addition, the two inductors L1 and L2 may include leakage inductors of a Common Mode Choke (CMC).
The power conversion device according to embodiment 4 configured as described above has the same operational advantages as the power conversion device according to embodiment 2, except that it has a synchronous step-up function.
Embodiment 5.
Fig. 5 is a circuit diagram showing a configuration example of a synchronous power conversion device having a step-up function according to embodiment 5. The power converter of embodiment 5 has the following differences from the power converter of fig. 4.
(1) There is also a bypass capacitor 18 connected in parallel with the dc voltage source 11.
(2) The other end of the bypass capacitor 13 is connected to the ground side of the load 15 via a fuse 19 that is cut when a current equal to or greater than a predetermined threshold current flows.
(3) The other end of the bypass capacitor 18 on the ground side is connected to a connection point between the bypass capacitor 13 and the fuse 19 via a second inductor L2 of the common mode choke coil (CMC) 17.
In the power converter configured as described above, the overcurrent of the bypass capacitors 13 and 18 can be suppressed by adding the fuse 19. By providing the common mode choke coil (CMC)17, the resonance frequency of the resonance circuit constituted by the combination of the inductors L1 and L2 of the common mode choke coil (CMC)17 and the bypass capacitors 12 and 13 can be lowered. Other operational effects of the present embodiment are the same as those of embodiment 4.
Examples
Fig. 6 is a simulation result of the power conversion apparatus of fig. 3, and is a graph showing frequency characteristics of the efficiency Ef and the ripple Ie of the execution current. The inventors performed a simulation for confirming the effect of resonance suppression using a circuit simulator (software name: simmetrix) using the circuit configuration of the power conversion device according to embodiment 3 of fig. 3. The following table 1 shows the simulation conditions thereof.
[ TABLE 1]
The resonance frequency fr is changed by changing the total inductance value of the inductors 14A and 14B. By making the resonance frequency fr smaller than the switching frequency fSWThe decrease in fluctuation Ie and the increase in efficiency Ef were confirmed. As can be seen from fig. 7, f is the number frSWWhen the efficiency Ef is lowered, the fluctuation Ie of the effective current is increased by making fr < fSWAnd fr ═ fSWCompared with the prior art, the efficiency Ef is improved, and the fluctuation Ie of the effective current is reduced.
Fig. 7 shows simulation results of the power conversion device of fig. 3, showing the resonant frequency fr and the switching frequency fSWTiming charts of the waveforms of the respective operation signals when they do not match (70 kHz). Fig. 8 is a simulation result of the power conversion device of fig. 3, showing the resonant frequency fr and the switching frequency fSWTiming charts of the waveforms of the respective operation signals when they are matched at (70 kHz). As can be seen from FIG. 8, when the resonant frequency fr and the switching frequency f are equalSWWhen the voltages are matched (70kHz), the ripple current and the ripple voltage increase. In contrast, when the resonance frequency fr is equal to the switching frequency fSWWhen the (70kHz) is inconsistent, the ripple current and the ripple voltage decrease.
Comparison with conventional example 1.
Fig. 11 is a graph showing the frequency characteristic of switching noise, which is a problem of the power converter of conventional example 1, and fig. 12 is a graph showing the frequency characteristic of switching noise, which is an operation effect obtained by a method for solving the problem in the present embodiment.
In the power converter of conventional example 1 shown in fig. 11, a plurality of IGBTs are used as power switching elements, and the switching frequency is 20kHz and is relatively low. In conventional example 1, 2 bypass capacitors are connected by a relatively low inductor, and the inductor with low inductance operates in a high frequency region where the noise level is low.
However, in the power converter of conventional example 1, the switching element of the switching circuit is increased in frequency by using the next-generation power semiconductor switching element (SiC or GaN), so that the power converter can be downsized and highly efficient. However, as the frequency increases, the resonance frequency between the bypass capacitors may be matched, which may lead to an increase in ripple, deterioration in efficiency, and a decrease in lifetime.
In particular, in the switching circuits 10A and 10B, when the switching elements in the switching circuit 10 malfunction, there is a possibility that an overcurrent flows from the bypass capacitors 12 and 13. In the present embodiment, since inductors 14A and 14B having inductance larger than that of the related art are disposed in the front stage of bypass capacitor 13 having a lower resonance frequency and a larger capacity than that of the related art, compared to the related art, an effect of suppressing an overcurrent can be obtained. In contrast, in the conventional example, the inductance of the inductor is smaller than that of the present embodiment, and therefore the overcurrent suppression effect is small.
In contrast, according to embodiments 1 to 4, as shown in fig. 12, the inductance of the inductor is increased to make the resonance frequency fr smaller than the switching frequency fSWThereby enabling to use a switching frequency f without generating switching noiseSWDriving is performed. In contrast, in conventional example 2, the resonance frequency fr is made larger than the switching frequency f by the reduction of the inductanceSWSo as to switch at a switching frequency f with a low noise levelSWDriving is performed. In the future, the switching elements are configured using the next-generation power devices, so that the power conversion apparatus is increased in frequency and the noise level increases in a high-frequency range.
Industrial applicability
As described above, according to the power conversion device of the present invention, it is possible to avoid complication of the circuit configuration, to reliably reduce switching noise in the power conversion device as compared with the conventional art, and to efficiently operate. Here, a component with relatively small ripple can be selected as the capacitor to be inserted, and an inductor is inserted to suppress an overcurrent, so that the heat radiator for the switching element can be made smaller than in the related art.
Description of the reference symbols
10. 10-1 to 10-M, 10A: a switching circuit; 11: a DC voltage source; 12. 13: a bypass capacitor; 14A, 14B: an inductor; 15: a load; 16: an inductor; 17: a Common Mode Choke (CMC); 18: a bypass capacitor; 19: a fuse; 20. 20-1-20-M, 20A: a control circuit; 30. 30A, 30B: a filter circuit; d1: a diode; l1, L2: an inductor; Q1-Q4: a switching element.
Claims (4)
1. A power conversion device having:
at least one switching circuit for switching at a predetermined switching frequency (f)SW) Switching the DC voltage to generate an AC voltage; and
a filter circuit for converting the AC voltage from the switch circuit into a DC voltage by low-pass filtering and outputting the DC voltage to a load,
it is characterized in that the preparation method is characterized in that,
the filter circuit has:
a first bypass capacitor that bypasses noise of a first frequency component in the alternating-current voltage from the switching circuit;
a second bypass capacitor that bypasses noise of a second frequency component lower than the first frequency component in the alternating-current voltage from the switching circuit; and
at least one inductor interposed between the first bypass capacitor and the second bypass capacitor,
the inductance (L) of the inductor is set such that the resonance frequency (fr) of the filter circuit is due to the insertion of the inductorBecomes higher than the switching frequency (f)SW) Is small.
2. The power conversion apparatus according to claim 1,
setting the capacitance of the first bypass capacitor to C1，
Setting the capacitance of the second bypass capacitor to C2，
The switching frequency (f)SW) And the resonance frequency (fr) is set as follows:
[ equation 1]
3. The power conversion apparatus according to claim 1 or 2,
the inductor includes at least one of a routing inductor, an assembly inductor, and an assembly coil.
4. The power conversion apparatus according to any one of claims 1 to 3,
the inductor comprises a leakage inductor of a Common Mode Choke (CMC) or at least two inductors constituting the Common Mode Choke (CMC).
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2018-136174 | 2018-07-19 | ||
| JP2018136174A JP6954240B2 (en) | 2018-07-19 | 2018-07-19 | Power converter |
| PCT/JP2019/009558 WO2020017090A1 (en) | 2018-07-19 | 2019-03-11 | Power conversion device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN112368926A true CN112368926A (en) | 2021-02-12 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201980045560.XA Pending CN112368926A (en) | 2018-07-19 | 2019-03-11 | Power conversion device |
Country Status (5)
| Country | Link |
|---|---|
| US (1) | US11329546B2 (en) |
| EP (1) | EP3826162A4 (en) |
| JP (1) | JP6954240B2 (en) |
| CN (1) | CN112368926A (en) |
| WO (1) | WO2020017090A1 (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP6973316B2 (en) * | 2018-07-19 | 2021-11-24 | オムロン株式会社 | Power converter |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH05111251A (en) * | 1991-10-11 | 1993-04-30 | Matsushita Electric Ind Co Ltd | Stabilized power source |
| CN1441539A (en) * | 1997-03-19 | 2003-09-10 | 株式会社日立制作所 | Power changer |
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| CN111869074A (en) * | 2018-03-07 | 2020-10-30 | 日产自动车株式会社 | Method for controlling resonance type power conversion device, and DC-DC converter |
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2019
- 2019-03-11 CN CN201980045560.XA patent/CN112368926A/en active Pending
- 2019-03-11 EP EP19838148.5A patent/EP3826162A4/en active Pending
- 2019-03-11 WO PCT/JP2019/009558 patent/WO2020017090A1/en active Application Filing
- 2019-03-11 US US17/259,500 patent/US11329546B2/en active Active
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| JPH05111251A (en) * | 1991-10-11 | 1993-04-30 | Matsushita Electric Ind Co Ltd | Stabilized power source |
| CN1441539A (en) * | 1997-03-19 | 2003-09-10 | 株式会社日立制作所 | Power changer |
| CN103299523A (en) * | 2011-01-17 | 2013-09-11 | 三菱电机株式会社 | Switching power supply device |
| JP2013236453A (en) * | 2012-05-08 | 2013-11-21 | Cosel Co Ltd | Switching power supply device |
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Also Published As
| Publication number | Publication date |
|---|---|
| WO2020017090A1 (en) | 2020-01-23 |
| EP3826162A1 (en) | 2021-05-26 |
| US11329546B2 (en) | 2022-05-10 |
| JP6954240B2 (en) | 2021-10-27 |
| EP3826162A4 (en) | 2022-04-06 |
| US20210167692A1 (en) | 2021-06-03 |
| JP2020014348A (en) | 2020-01-23 |
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